Show when nothing will resume a thread

[dominic-r]

An agent often ends a turn with a promise like "once the release lands I'll verify it" while holding nothing T3 Code can wake it from: no running background task or monitor, no watched pull request, no open delegated thread, no scheduled task bound to the thread. Nothing will ever start another turn, but in the sidebar the thread looks the same as one that is genuinely waiting, so users find out only when they check in and type "continue".

In one install's event log over about seven weeks, the user sent 424 messages that only nudged a stopped agent ("progress", "continue"). 171 of them came after a turn that ended with such a promise, and in 129 of those the agent held nothing T3 Code could wake it from. Half the nudges came within 6 minutes of the turn ending, and a tenth came more than 72 minutes later.

Proposal: when a thread's latest turn has ended and the thread has no pending wake source, show it as idle ("Nothing will resume this thread") in the sidebar and thread header, distinct from a thread that is waiting on something tracked. The state comes from existing data and doesn't parse the agent's text. A thread has a pending wake source if it has any of:

• a running or awaited background task
• an active PR watch
• an open delegated thread
• a bound scheduled task
• a pending approval or user input

#29887 implements this for web and mobile. It was opened before this discussion, so it lacks the prior approval CONTRIBUTING asks for. I'm happy to change or close it to fit whatever direction you prefer.

Open questions:

• Background-task wakes are confirmed only for Claude. Should a running task count as a wake source for every provider?
• An older server that doesn't report background work could make a held thread look idle.

Related: #27243, where a thread with a bound scheduled task shows no tag and looks idle.

Written by Claude Opus 5.5 in Claude Code, run from T3 Code.